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In the Forum: Horn-Loaded Speakers
In the Thread: Adding one more spherical to Macondo.
Post Subject: Controlling my own leak!Posted by jessie.dazzle on: 8/11/2007
Romy,
Ok... I tried it... I backed off the screws securing the rear cover on one of the S2s I use with a pair of 180Hz horns. I backed off each screw a total of two turns, leaving a gap of 1.5mm.
I also did some measuring, and had left a 400Hz tone playing when I backed off the screws; I was surprized at just how much sound came out the rear once I vented the cover.
All listening and measuring was done using only one channel, with only the one 180Hz horn connected and band-passed as usual at 790-3200Hz.
Sound ; vented vs. sealed :
With this horn there is not that much difference... Playing a pure tone reveals that with the cover vented the sound goes slightly softer. With a male voice playing I would say that there is a sort of slight effect of increased depth (reminds me of an echo).
I am unable to post the image directly, but below is a link to the measured results taken while playing a closely spaced series of tones from a tone generator at constant volume... I used the exact same set up, and played the exact same series of tones both with cover tight and vented.
The vented cover measures almost identically in my horn... The only area of significant divergence happens at just below 600Hz, where the vented cover driver surprisingly drops out, leaving about a 100Hz gap (click on link to see graph). I ran the test several times to make sure, and got the same results each time.
I don't know why you are getting such clearly better results from your horn with a vented driver.
Now that I have all the measurement stuff out, I think I'll take a "look" at the other horns...
jd*
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